When sealing fluid transmittable openings in a well, such as in a petroleum well, it is usual to move a seal having an elastic element of a larger external diameter than the diameter of the fluid transmittable opening to be sealed, into the fluid transmittable opening. By the elastic element being arranged between two shoulders, the volume that the elastic element may occupy is restricted, whereby a greater surface pressure is achieved between the elastic element and the inner jacket of the fluid transmittable opening, as compared to if the elastic element could lengthen freely.
During operation, damage may occur in the sealing surface of well components. For example, during wireline operations in the well, it is not unusual for one or more axial grooves to be worn into the sealing surface of a downhole safety valve. Other causes may cause other types of damage in the sealing surfaces.
Known seals often cannot be brought to seal damaged fluid transmittable openings. The reason is that the damage is not filled by the elastic element and thereby sufficient sealing of the damage for a differential pressure to be established across the elastic element is not achieved.
As known seals notoriously provide an unreliable seal, it is usual to place a seal outside the damaged sealing surface. Seals of this kind may be functionally unreliable, which has turned out to possibly result in operational interruptions and need for repairs.